Question

我使用bootstrap 3创建旋转木马：

HTML：

<div id="myCarousel" class="carousel slide">
    <div class="carousel-inner">
        <div class="active item">
            <img src="http://rivathemes.net/html/envor/img/posts/3.jpg" class="img-big">
        </div>
        <div class="item">
            <img data-lazy-load-src="http://rivathemes.net/html/envor/img/posts/4.jpg" class="img-big">
        </div>
    </div>
    <div class="carousel-controls">
<a class="left carousel-control" href="#myCarousel" data-slide="prev"><i class="fa fa-angle-double-left fa-lg"></i></a>

<a class="right carousel-control" href="#myCarousel" data-slide="next"><i class="fa fa-angle-double-right fa-lg"></i></a>

    </div>
</div>

并添加此代码以添加img延迟加载。

JS：

$('#myCarousel').on('slid', function () {
    var $nextImage = $('.active.item', this).next('.item').find('img');
    $nextImage.attr('src', $nextImage.data('lazy-load-src'));
});

但是，这对我不起作用！？可以解决这个问题吗？

重要问：我可以为延迟加载添加图像预加载器吗？！

DEMO：FIDDLE

Answer 1

answer by dm4web不会通过直接点击轮播指示符来考虑跳过幻灯片。此版本正确加载图像，无论您如何滑动图像，都使用Bootstrap event.relatedTarget（项目滑入到位，请参阅the official documentation）。尝试运行下面的代码段，然后点击指示灯以切换前面的几张幻灯片。

＆＃13;

var cHeight = 0;

$('#carousel-example-generic').on('slide.bs.carousel', function(e) {

  var $nextImage = $(e.relatedTarget).find('img');

  $activeItem = $('.active.item', this);

  // prevents the slide decrease in height
  if (cHeight == 0) {
    cHeight = $(this).height();
    $activeItem.next('.item').height(cHeight);
  }

  // prevents the loaded image if it is already loaded
  var src = $nextImage.data('lazy-load-src');

  if (typeof src !== "undefined" && src != "") {
    $nextImage.attr('src', src)
    $nextImage.data('lazy-load-src', '');
  }
});

＆＃13;

<link href="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.5/css/bootstrap.min.css" rel="stylesheet" />
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<script src="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.5/js/bootstrap.min.js"></script>

<div class="container-fluid">

  <div id="carousel-example-generic" class="carousel slide" data-ride="carousel">
    <!-- Indicators -->
    <ol class="carousel-indicators">
      <li data-target="#carousel-example-generic" data-slide-to="0" class="active"></li>
      <li data-target="#carousel-example-generic" data-slide-to="1"></li>
      <li data-target="#carousel-example-generic" data-slide-to="2"></li>
      <li data-target="#carousel-example-generic" data-slide-to="3"></li>
      <li data-target="#carousel-example-generic" data-slide-to="4"></li>
    </ol>

    <!-- Wrapper for slides -->
    <div class="carousel-inner" role="listbox">
      <div class="item active">
        <img src="http://placehold.it/5000x1000">
      </div>
      <div class="item">
        <img data-lazy-load-src="http://placehold.it/5001x1000">
      </div>
      <div class="item">
        <img data-lazy-load-src="http://placehold.it/5002x1000">
      </div>
      <div class="item">
        <img data-lazy-load-src="http://placehold.it/5003x1000">
      </div>
      <div class="item">
        <img data-lazy-load-src="http://placehold.it/5004x1000">
      </div>
    </div>

    <!-- Controls -->
    <a class="left carousel-control" href="#carousel-example-generic" role="button" data-slide="prev">
      <span class="glyphicon glyphicon-chevron-left" aria-hidden="true"></span>
      <span class="sr-only">Previous</span>
    </a>
    <a class="right carousel-control" href="#carousel-example-generic" role="button" data-slide="next">
      <span class="glyphicon glyphicon-chevron-right" aria-hidden="true"></span>
      <span class="sr-only">Next</span>
    </a>
  </div>

</div>

＆＃13;

Answer 2

http://jsfiddle.net/ys4je40u/

将lazy-load类添加到项目对象
使用slide.bs.carousel活动

<强> CSS：

.lazy-load {
    background: url("http://www.mozart.it/images/preloader.gif") center center no-repeat;
}

JQ：

var cHeight = 0;

$('#myCarousel').on('slide.bs.carousel', function (e) {
    var $nextImage = null;

    $activeItem = $('.active.item', this);

    if (e.direction == 'left'){
        $nextImage = $activeItem.next('.item').find('img');
    } else {
        if ($activeItem.index() == 0){
            $nextImage = $('img:last', $activeItem.parent());
        } else {
            $nextImage = $activeItem.prev('.item').find('img');
        }
    }

    // prevents the slide decrease in height
    if (cHeight == 0) {
       cHeight = $(this).height();
       $activeItem.next('.item').height(cHeight);
    }

    // prevents the loaded image if it is already loaded
    var src = $nextImage.data('lazy-load-src');

    if (typeof src !== "undefined" && src != "") {
       $nextImage.attr('src', src)
       $nextImage.data('lazy-load-src', '');
    }
});

Answer 3

如果幻灯片中有多个图像，则必须使用：

var cHeight = 0;

$('#carousel').on('slide.bs.carousel', function (e) {
    var $nextImage = null;

    $activeItem = $('.active.item', this);

    if (e.direction == 'left'){
        $nextImage = $activeItem.next('.item').find('img');
    } else {
        if ($activeItem.index() == 0){
            $nextImage = $('img:last', $activeItem.parent());
        } else {
            $nextImage = $activeItem.prev('.item').find('img');
        }
    }

    // prevents the slide decrease in height
    if (cHeight == 0) {
       cHeight = $(this).height();
       $activeItem.next('.item').height(cHeight);
    }

    // => Changes here ! 
    // prevents the loaded images if it is already loaded
    $nextImage.each(function(){
        var $this = $(this),
            src = $this.data('original');

        if (typeof src !== "undefined" && src != "") {
           $this.attr('src', src)
           $this.data('original', '');
        }
    });
});

延迟加载在bootstrap轮播中不起作用

3 个答案: